Accelerating advances in continental domain hydrologic modeling

In the past, hydrological modeling of surface water resources has mainly focused on simulating the hydrologic cycle at local to regional catchment modeling domains. There now exists a level of maturity amongst the catchment, global water security, and land surface modeling communities such that these communities are converging towards continental domain hydrologic models. This commentary, written from a catchment hydrology community perspective, provides a review of progress in each community towards this achievement, identifies common challenges the communities face, and details immediate and specific areas in which these communities can mutually benefit one another from the convergence of their research perspectives. Those include: (1) creating new incentives and infrastructure to report and share model inputs, outputs, and parameters in data services and open access, machine-independent formats for model replication or re-analysis; (2) ensuring that hydrologic models have: sufficient complexity to represent the dominant physical processes and adequate representation of anthropogenic impacts on the terrestrial water cycle, a process-based approach to model parameter estimation, and appropriate parameterizations to represent large-scale fluxes and scaling behaviour; (3) maintaining a balance between model complexity and data availability as well as uncertainties and (4) quantifying and communicating significant advancements towards the modeling goals.